1. Field of the Invention
The present invention relates to a press molding apparatus, a press mold, and a press molding method, for transferring the features of a mold to a work (workpiece) under the application of pressure.
2. Description of the Related Art
In recent years, micro-fabrication technology for press transferring fine structures on a mold to a workpiece, such as resin or metal, have been developed and become a focus of attention. This technology, called nano-imprint or nano-embossing, has a resolution on the order of several nanometers. In addition, it can mold 3D structures on a wafer by one operation. For these reasons, this technology is expected to be applicable to a wide variety of fields, such as the next-generation semiconductor fabrication, the fabrication of optical elements like photonic crystals, and the fabrication of biochips such as μ-TAS chips.
There have also been proposed methods of pressing a mold into a resist on a semiconductor wafer to create an imprint pattern so as to produce a pattern on the semiconductor wafer through the process of ion milling.
There is disclosed a method of pressing a mold into a resist to mold the resist and etching the resist pattern to form holes in a wafer on which the resist has been carried (U.S. Pat. No. 5,772,905).
The following describes the current state of the above-mentioned molding technology with reference to FIGS. 4 to 6.
FIG. 4 shows a typical example of the structure of the prior art technology. A mold 104 is typically micro-fabricated on a wafer of Si or SiO2 by EB lithography, FIB, X-ray lithography, etc, or replicated by Ni electroforming. A work is typically resin 105 coated on a wafer 106 of a desired material, or a resin plate. The mold 104 and the work (workpiece) are sandwiched between a mold pressing member 103 and a wafer pressing member 107, and pressed together by means of a press mechanism (not shown).
FIG. 5 shows a pressed state in the structure of FIG. 4. In this case, the pressing members, the mold 104, and the wafer 106 are partially deformed, crushing a large recess almost flat. As a result, since the work is molded as shown in FIG. 6, the accuracy of shaping the work is reduced. Such a phenomenon becomes noticeable as the molding pressure increases or the recessed area is shallower.
It is therefore desired to have a molding technique capable of transferring features with a high degree of precision for finer fabrication by reducing the deformation of a mold and a work in the vicinity of a recess on the mold.